Method and apparatus for abatement of reaction products from a vacuum processing chamber

ABSTRACT

An exemplary method and apparatus for abating reaction products from a vacuum processing chamber includes a reaction chamber in fluid communication with the vacuum processing chamber, a coil disposed about the reaction chamber, and a power source for supplying RF energy to the coil. The coil creates a plasma in the reaction chamber which effectively breaks down stable reaction products from the vacuum processing chamber such as perfluorocarbons (PFCs) and hydrofluorocarbons (HFCs) which significantly contribute to global warming. According to alternative embodiments, the plasma may be generated with grids or coils disposed in the reaction chamber perpendicular to the flow of reaction products from the vacuum processing chamber.

FIELD OF THE INVENTION

The present invention relates generally to vacuum processing chambersand more particularly to a method and apparatus for abatement ofreaction products such as perfluorocarbons and hydrofluorocarbons invacuum processing chambers.

BACKGROUND OF THE INVENTION

Various types of equipment exist for semiconductor processing such asplasma etching, ion implantation, sputtering, rapid thermal processing(RTP), photolithography, chemical vapor deposition (CVD), and flat paneldisplay fabrication processes wherein etching, resist stripping,passivation, deposition, and the like, are carried out. For example, avacuum processing chamber may be used for etching and chemical vapordeposition of materials on substrates by supplying an etching ordeposition gas to the vacuum chamber and by application of radiofrequency (RF) energy to the gas. Electromagnetic coupling of RF energyinto the source region of a vacuum chamber is conventionally employed togenerate and maintain a high electron density plasma having a lowparticle energy. Generally, plasmas may be produced from a low-pressureprocess gas by inducing an electron flow which ionizes individual gasmolecules through the transfer of kinetic energy through individualelectron-gas molecule collisions. Most commonly, the electrons areaccelerated in an electric field, typically a radiofrequency electricfield produced between a pair of opposed electrodes which are orientedparallel to the wafer.

Plasma generation is used in a variety of such semiconductor fabricationprocesses. Plasma generating equipment includes parallel plate reactorssuch as the type disclosed in commonly owned U.S. Pat. No. 4,340,462,electron cyclotron resonance (ECR) systems such as the type disclosed incommonly owned U.S. Pat. No. 5,200,232, and inductively coupled plasma(ICP) or transformer coupled plasma systems such as the type disclosedin commonly owned U.S. Pat. No. 4,948,458.

Due to the tremendous growth in integrated circuit production, the useof vacuum processing chambers has increased dramatically in recentyears. The use of vacuum processing chambers may seriously affect theenvironment, however, because perfluorocarbons (PFCs) are widely used inplasma etch and plasma-enhanced CVD equipment. PFCs are highly stablecompounds which makes them well suited for plasma processing. However,PFCs also significantly contribute to global warming and are notdestroyed by scrubbers or other conventional emission control equipmentused in vacuum processing chambers. Although there are many gasses whichcause global warming, PFCs and hydrofluorocarbons (HFCs), both of whichare referred to hereinafter as “fluorocarbons”, also used in plasmaprocessing, have particularly high global warming potentials (GWPs). Forexample, CF₄, C₃F₈, SF₆, NF₃, and C₂HF₅ all have GWPs of over 3000, andC₂F₆, SF₆, and CHF₃ have GWPs of over 12,000. By contrast, carbondioxide, a well-known greenhouse gas, has a GWP of 1. In addition,because of their stability, PFCs have a very long lifetime. For example,the lifetimes of CF₄ and C₂F₆ are 50,000 and 10,000 years, respectively.Thus, collectively, these process gasses can have a significant impacton the environment.

To reduce the impact of PFCs on the environment, several conventionalmethods for abating PFCs from vacuum processing chambers have beenproposed, including process optimization, chemical alternatives, anddestruction/decomposition. Process optimization involves the refinementof system parameters to achieve the desired process while using theminimum amount of PFCs. Process optimization is desirable because itreduces chemical costs and emissions and may increase throughput andprolong the life of internal components of the reactor. However, processoptimization does not provide a complete solution since it does notinvolve the abatement of PFCs once they are used in the system. Thus,although the amount of PFCs used is reduced by process optimization, thePFCs that are used are ultimately emitted into the environment.

Chemical alternatives to using PFCs are desirable because they eliminatethe problem of PFC emissions entirely. However, to date, research isstill underway to uncover more effective and environmentally soundchemical alternatives.

There are two basic categories for conventionaldestruction/decomposition techniques. The first category involvesabatement performed on the atmospheric side of the system, either ateach tool or on a large scale for multiple tools, after the gasses havepassed through the pumping system. On the atmospheric side, there areseveral possibilities, including water scrubbers, resin beds, furnaces,flame-based burn boxes, and plasma torches. All of these except burnboxes and torches are ineffective against many of the highly stable PFCcompounds.

Burn boxes have been shown to be inefficient abatement devices, unlessvery large amounts of reactant gases such as hydrogen, methane, ornatural gas are flowed through the burn box. This makes these devicesvery expensive to operate, and environmentally unfriendly.

Plasma torches on the atmospheric side could be more effective; however,very large and expensive, not to mention dangerous, torch facilitieswould be required to abate what would be a small concentration of PFCsin a very high flow of tool effluent. This inefficiency is exacerbatedby the addition of large amounts of nitrogen, used as a diluent invacuum pumps and as a purge gas in many tool operations.

The second general category of destruction/decomposition techniquesinvolves abatement performed under a vacuum upstream of the pumpingsystem. Plasma destruction is one method, for example, in which a deviceis employed to treat the exhaust from the tool upstream of the pumpbefore nitrogen purge dilution has taken place. In plasma destruction,energy is applied to the reaction gasses to create a plasma in which thegasses are ionized. The PFCs become unstable at the high energy state,and are consequently broken down into smaller molecules which are lessdetrimental to the environment.

Examples of devices for plasma destruction include the ETC Dryscrub andthe Eastern Digital Post-Reaction Chamber (PRC). The ETC Dryscrub is aflat spiral chamber. The gases come in at the outer end of the spiral,circle around, and eventually exit through the center of the spiral. Thespiral is an RF electrode operated at 100 kHz. The purpose of thereactor is to dissociate exhaust gases coming from a CVD system so thatany remaining solid-producing gases are reacted onto the walls of thespiral. Tests performed on the ETC Dryscrub reactor, however, resultedin a relatively ineffective abatement of C₂F₆, the test gas. Inaddition, the main reaction product was another greenhouse PFC gas, CF₄,and most of the secondary products were also greenhouse gasses. TheEastern Digital PRC is essentially the same as the ETC Dryscrub, andyields similar results. These devices are both inefficient at plasmaabatement and have low plasma densities and dissociation rates.

Another known method for plasma destruction, in which CF₄, C₂F₆, and SF₆may be abated, involves the use of a microwave plasma reactor. Microwavesources, however, are expensive and complex. They also have small skindepths, so they tend have an axial region where there is no plasma,through which unabated gases escape. This can be compensated byinserting a “plug”, but the plug then reduces the fluid conductance ofthe device, which in turn adversely affects the performance of thepumping system.

SUMMARY OF THE INVENTION

According to an exemplary embodiment of the invention, an apparatus forabating fluorocarbons in gas reaction products from a vacuum processingchamber comprises a dielectric tube in fluid communication with anoutlet port of the vacuum processing chamber, a coil disposed around thedielectric tube, and an RF source, connected to the coil, for supplyingRF energy to the coil and destroying fluorocarbons in the gas.

By applying RF power to the coil, an inductively coupled plasma (ICP) isgenerated in the dielectric tube which breaks down the reaction productsfrom the vacuum processing chamber. The abatement device providesseveral advantages over prior systems. For example, in contrast to manyprior designs, the abatement device can be made to be simple, compact,inexpensive, efficient, reliable, and require little or no operator orcontrol system intervention. The abatement device also provides a highplasma density, high dissociation rate operation, and a skin depth whichis adjustable through the frequency. This results in efficient abatementwithout compromising foreline conductance.

According to alternative embodiments, the plasma may be generated withgrids or coils disposed in the reaction chamber perpendicular to theflow of reaction products from the vacuum processing chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of the presentinvention will be more readily understood upon reading the followingdetailed description in conjunction with the drawings in which:

FIG. 1 is an illustration of an abatement apparatus according to anexemplary embodiment of the invention;

FIG. 2 is an illustration of one embodiment of a reactor tube;

FIG. 3 is an illustration of one embodiment of the plasma reactor ofFIG. 1 which includes the reactor tube of FIG. 2;

FIG. 4 is an illustration of the exemplary matching network of FIG. 3;

FIG. 5 is an illustration of another embodiment of the plasma reactor ofFIG. 1;

FIG. 6 is an illustration of another embodiment of the plasma reactor ofFIG. 1; and

FIG. 7 is an illustration of an exemplary scrubber shown in FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, a fluorocarbon (e.g. perfluorocarbon and/orhydrofluorocarbon) abatement apparatus according to an exemplaryembodiment of the invention generally comprises a plasma reactor 100which includes an RF power source 102 for supplying power to the plasmareactor 100. The abatement apparatus is preferably installed in theforeline 104 of each vacuum processing chamber at the point of use.According to a preferred embodiment, the abatement apparatus comprises asection of dielectric tubing replacing a section of foreline. Theabatement apparatus shown in FIG. 1 may thus be installed downstream ofa vacuum processing chamber 106. According to a preferred embodiment, acoil wrapped around the dielectric tube is driven with RF power in orderto generate an inductively coupled plasma (ICP) within the foreline. Theplasma breaks down reaction products from the vacuum processing chambersuch as PFCs and HFCs.

The plasma reactor 100 preferably includes a cooling mechanism 108, suchas a water cooler or a fan, for dissipating heat created by the plasmain the plasma reactor 100. For example, the plasma reactor 100 mayinclude a water jacket in which water is circulated to absorb heat inthe plasma reactor 100, or a fan.

The abatement apparatus may also include a reactant mixing chamber 110upstream of the plasma reactor 100 for mixing a reactant into the gasflow before it reaches the plasma reactor 100. The reactant mixingchamber 110 is supplied with the reactant by a reactant source 112.According to a preferred embodiment, water vapor is used as the reactantto supply hydrogen and oxygen to the reaction. The reactant may alsoinclude a compound such as H₂, CH₄, or other hydride to supply hydrogento the reaction, and O₂ to supply oxygen to the reaction.

A scrubber 114 can be installed downstream of the plasma reactor 100 toremove HF to prevent damage of the remaining foreline and/or mechanicalpump by HF which is a highly corrosive gas. The scrubber 114 may includea material such as Si or W in the form of pellets, beads, chunks, lines,baffles, screens, etc., which reacts with HF. Downstream of thescrubber, an emission monitoring or sampling unit 116 may be provided tomonitor the content of the effluent gasses.

FIGS. 2 and 3 are illustrations of a plasma reactor 100A according to apreferred embodiment of the invention. The plasma reactor 100A maygenerally comprise a dielectric tube 120 through which reaction productsfrom the vacuum processing chamber 106 flow. The dielectric tube 120 ispreferably divided into three sections, as shown in FIG. 2. The middlesection 122 preferably comprises quartz because of its ability towithstand high temperatures. Two end sections 124, which are preferablymade of glass, are sealed to the quartz tube 122. The glass end sections124 are also sealed to a metal foreline tube 126, which can be astandard ISO NW50 flange. The glass end sections 124 are providedbecause it is difficult to bond quartz directly to metal.

According to one embodiment, the tube shown in FIG. 2 is about 13 incheslong from flange to flange with an inner diameter of about 2 inches andan outer flange diameter of about 3 inches. The quartz section 122 maybe about 10 inches long and the two glass sections 124 may each be 2inches long. These dimensions are of course provided only as an exampleand are not intended to be limiting.

As shown in FIG. 3, a coil 130 is provided to generate a high densityplasma source which efficiently abates PFCs and other products from thevacuum processing chamber 106. The coil 130 preferably encircles theinner quartz section 122 but not the glass end sections 124 so that theglass end sections 124 remain at a lower temperature.

FIG. 3 shows the exemplary plasma reactor 100A implemented as part of avacuum processing apparatus. The foreline 104 of the apparatus is at lowpressure and contains reaction products from the vacuum processingchamber. The pressure inside the dielectric tube may range from about 30mTorr to 3 Torr, for example, and preferably is about 200 mTorr.

A bellows 134 may be provided between the foreline 104 and the plasmareactor 100 and may be attached to the foreline 104 with a flange 136.The bellows 134 provides strain relief to the dielectric tube 120 of theplasma reactor 100A. Thus, any strain caused by movement of the foreline104 with respect to the plasma reactor 100A may be alleviated with theflexible bellows 134 so that the dielectric tube 120 of the plasmareactor 100A is not damaged. The dielectric tube 120 can be furtherprotected by securely attaching it to the rigid enclosure 136 in whichit is located. The walls of the rigid enclosure 136, which may be metaland which are fixed to the dielectric tube 120, provide additionalresistance to strains imparted on the dielectric tube 120 by movement ofthe foreline 104.

The apparatus may also include an RF shielding seal 138 at the junctionbetween the reactor tube 120 and the rigid enclosure 136 in which thereactor tube 120 is located. The RF shielding seal 138 prevents RFradiation generated by the coil 130 from interfering with nearbyelectronic devices. An RF feed through connector 140 may be installed onthe enclosure 136 to transmit RF power to the interior of the enclosure136.

To control the power applied through the coil 130 and to adjust theresonant frequency of the coil 130, a matching network 142 can beprovided. The matching network 142 is preferably simple and inexpensive.As shown in FIGS. 3 and 4, the matching network 142 may include a firstvariable capacitor C₁ connected at one side to ground and at the otherside to the RF power source 102 and to one end of the coil 130. A secondvariable capacitor C₂ may be connected between ground and the other endof the coil 130. The capacitance of the variable capacitors C, and C₂may be adjusted in any suitable manner, such as with knobs 143, toadjust the circuit resonance frequency with the frequency output of theRF generator 102 and to cancel the inductive reactance of the coil 130.Impedance matching maximizes the efficiency of power transfer to thecoil 130. Those skilled in the art will recognize that other types ofmatching networks 142 can be used in conjunction with the presentinvention.

When the coil 130 is powered by the power source 102, two examples ofthe chemical reactions of two PFCs, C₂F₆ and SF₆ are as follows:

EXAMPLE 1

C₂F₆------->CF₃+CF₃O₂------->O+OCOF₂------->COF+FCO₂------->CO+OF₂------->F+FCOF+O------->CO₂+FCF₃+O------->COF₂+FCF₃+CF₃+M------->C₂F₆+MO+O+M------->O₂+MCOF+F+M------->COF₂+MCO+O+M------->CO₂+MF+F+M------->F₂+MCO+F+M------->COF+M

EXAMPLE 2

SF₆+O₂------->SO₂+3F₂SF₆+O₂------->SO₂F₂+2F₂

According to one embodiment of the invention, a reactant injector 110 isprovided upstream of the plasma reactor, as shown in FIG. 1. Thereactant injector 110 delivers chemicals with which to react away thePFC compounds, which otherwise could simply recombine downstream of theplasma reactor. The preferred embodiment is a water vapor injector. Thehydrogen from the water reacts with the fluorines of the PFCs to produceHF. The HF may then be removed either by the scrubber chamber 114upstream of the pump or by a conventional scrubber on the atmosphericside. The oxygen reacts with carbon, sulphur and/or nitrogen to produceCOx, SOx and NOx, which are less harmful global warning gases than PFCs,and which may be removed from the emission stream by scrubbers. Varioushydrides may also be produced and removed by scrubbing, as well aspolymers and inorganic solids which will deposit on the reactor walls.The reactor, therefore, is preferably designed to be easy to clean orreplace. Water vapor is preferred as the reactant because it is muchless expensive than the reactants H₂, CH₄ or other hydrides and O₂commonly used in abatement systems to supply hydrogen and oxygen to thereaction. The flowrate of the total reactant (e.g. water vapor, H₂, CH₄and/or O₂) supplied by the reactant source 112 may be approximatelyequal to the flowrate of the process gasses from the vacuum processingchamber, for example 50-1000 cubic centimeters at standard temperatureand pressure per minute. The reactant or reactants are preferablysupplied in an amount effective for minimizing recombination of thedissociated PFC's.

Downstream of the plasma reactor 100 may be a scrubber chamber 114 orsection of foreline which contains materials that react with the HF,such as Si or W in the form of pellets, beads, chunks, liners, baffles,screens, etc., as shown in FIGS. 1 and 7. In FIG. 7, the scrubberchamber 114 includes an inner section 115 of porous HF reactivematerials such as Si or W in the form of mesh, gravel, etc. The scrubberchamber 114 also includes an outer wall 117 which comprises HF reactivematerial. The provision of such a chamber 114 reduces the likelihood ofdamage of the remaining foreline and/or mechanical pump by HF, which isa highly corrosive gas. Although HF is easily handled by a scrubber onthe atmospheric side, the lifetime of the vacuum plumbing and pumps canbe increased significantly by providing a scrubber chamber 114 upstreamof the vacuum plumbing and pumps.

According to another embodiment of the invention, the plasma reactor maycomprise conductive elements inside the foreline to generate a plasma.As shown in FIG. 5, the elements of the plasma reactor 100B may be inthe form of conductive grids 150 through which the gases flow. Adjacentgrids 150 are oppositely charged with an RF generator 152 to generate acapacitive plasma. The reaction products, e.g., PFCs, are unstable inthe high energy plasma, and are consequently reacted into smaller, lessharmful molecules as described above. The grids 150 are preferablyplanar with the plane of the grid oriented perpendicular to the flow ofreaction products from the vacuum processing chamber. To generate acapacitive plasma, at least two grids 150 are used. To further enhancethe effectiveness of the plasma reactor, additional grids 150 can beprovided. The additional grids alternate in polarity so that eachadjacent pair of grids 150 acts as a capacitor. The grids 150 maycomprise a plasma resistant material for a long lifetime. Alternatively,the grids may comprise a consumable material or materials for enhancedabatement capacity.

The grids 150 are preferably disposed in a chamber 154 which has alarger cross sectional area than the cross sectional area of theforeline. In this way, the fluid conductance of the plasma reactor 100Bis not compromised. In addition, a fan or other cooling device can beprovided to dissipate heat created by the conductive grids 150. As inthe previous embodiment, a matching network 156 can be provided tomaximize or control the power delivered to the grids 150.

According to another embodiment of the invention, an exemplary plasmareactor 100C comprises at least one and preferably two or moretransformer coupled plasma coils. The transformer coupled plasma coils160, as shown in FIG. 6, have a generally spiral, planar configurationand are preferably oriented such that the plane of the coil isperpendicular to the flow of reaction products. The transformer coupledplasma coils 160 are coupled, preferably through a matching network 166,to an RF generator 162. By resonating a radiofrequency current throughthe coils 160, a planar magnetic field is induced which induces agenerally circular flow of electrons within a planar region parallel tothe plane of the coil 160. The circulating electrons create a plasma byionizing individual gas molecules through the transfer of kinetic energyfrom individual electron-gas molecule collisions.

The reaction products, e.g., PFCs, are unstable in the high energyplasma, and are consequently reacted into smaller molecules as describedabove. Preferably, at least two coils 160 are provided so that theperiod of time during which the reaction products are in the plasmastate is sufficiently long to effectively break down the reactionproducts. The provision of additional coils 160 thus increases the sizeof the region which the plasma occupies so that for a given flowrate,the reaction products are in the plasma state for a longer time. Thetransformer coupled plasma coils can comprise plasma resistant materialsfor a long lifetime. Alternatively, the transformer coupled plasma coilscan comprise a consumable material or materials for enhanced abatementcapacity. So that the fluid conductance of the apparatus is notcompromised, the chamber 164 in which the transformer coupled plasmacoils 60 are located can have an enlarged cross sectional areaperpendicular to the flow. A fan or other cooling mechanism can beprovided to dissipate heat generated by the coils 160 of the plasmareactor 100C.

Those skilled in the art will recognize that exemplary embodiments ofthe present invention provide significant advantages in the abatement ofreaction products such as fluorocarbons from a vacuum processingchamber. For example, in contrast to many prior designs, the reactor canbe made to be simple, compact, inexpensive, efficient, reliable, andrequire little or no operator or control system intervention. The plasmareactor also provides a high plasma density, high dissociation rateoperation, and a skin depth which is adjustable through the frequency.This results in efficient abatement without compromising forelineconductance. Also, in the event that an abatement device fails, only onetool is affected, rather than an entire section of a processing system.

The above-described exemplary embodiments are intended to beillustrative in all respects, rather than restrictive, of the presentinvention. Thus the present invention is capable of many variations indetailed implementation that can be derived from the descriptioncontained herein by a person skilled in the art. All such variations andmodifications are considered to be within the scope and spirit of thepresent invention as defined by the following claims.

1. An abatement method for destroying fluorocarbons consistingessentially of gaseous fluorocarbons exhausted from a vacuum processingchamber in which a semiconductor substrate is processed, the methodcomprising the steps of: processing the semiconductor substrate in thevacuum processing chamber thereby producing gaseous reaction productsincluding the gaseous fluorocarbons; flowing an exhaust gas containingfluorocarbons consisting essentially of the gaseous fluorocarbons fromthe vacuum processing chamber through a reaction chamber downstream ofthe vacuum processing chamber; introducing water vapor as a reactantinto the exhaust gas proximate to the vacuum processing chamber in anamount effective to minimize recombination of dissociated fluorocarbons,hydrogen from the water vapor reacting with the dissociatedfluorocarbons so as to form HF, and oxygen from the water vapor reactingwith at least one of C, S and N in the exhaust gas to form at least oneof the gases COx, SOx, and NOx, or a mixture thereof in gaseous form;and applying RF Power to the gas in the reaction chamber to generate aplasma in the reaction chamber which dissociates the fluorocarbons inthe exhaust gas.
 2. The method of claim 1, wherein the pressure in thereaction chamber is less than atmospheric pressure.
 3. The method ofclaim 1, wherein the water vapor is injected as the reactant into theflow of gas upstream of the reaction chamber.
 4. The method of claim 1,further comprising the step of controlling the amount of RF powerapplied to the fluorocarbons with a matching network.
 5. The method ofclaim 1 wherein the vacuum processing chamber comprises a high densityplasma reactor and the exhaust gas is produced while etching asemiconductor substrate.
 6. The method of claim 1, wherein the vacuumprocessing chamber comprises a high density plasma reactor and theexhaust gas is produced during chemical vapor deposition of a materialon a semiconductor substrate.
 7. The method of claim 1, wherein theexhaust gas has a flow rate equal to a flow rate of process gasesexhausted from the vacuum processing chamber.
 8. The method of claim 1,wherein the exhaust gas flows continuously through the reaction chamberduring the step of applying RF power to the gas in the reaction chamber.9. The method of claim 1, wherein the HF is removed from the exhaust gasby a scrubber downstream from the reaction chamber.
 10. The method ofclaim 1, wherein the reactant and the exhaust gas flow through thereaction chamber at flow rates of 50 to 1000 sccm.
 11. The method ofclaim 1, wherein the reactant and the exhaust gas flow through thereaction chamber at approximately equal flow rates.
 12. The method ofclaim 1, wherein the RF power is applied to the gas in the reactionchamber with a plurality of conductive elements arranged within thereaction chamber.
 13. The method of claim 12, wherein the conductiveelements comprise coils.
 14. The method of claim 12, wherein theconductive elements comprise grids.
 15. The method of claim 1, furthercomprising reacting gas exhausted from the reaction chamber with ascrubber comprising at least one of Si and W in the form of at least oneof beads, pellets, chunks, a liner, a baffle, a screen and a grid. 16.The method of claim 1, wherein the introduction of water vapor as areactant into the exhaust gas proximate to the plasma processing chambercomprises introducing vapor into a foreline of the vacuum processingchamber.
 17. The method of claim 1, wherein generating a plasma in thereaction chamber by applying RF power to the gas comprises applying RFpower to at least one transformer coupled plasma (TCP) coil to induce aplanar magnetic field which induces a flow of electrons within a planarregion parallel to the plane of the at least one TCP coil, wherein theflow of electrons creates a plasma by ionizing gas molecules.
 18. Anabatement method for destroying fluorocarbons consisting essentially ofgaseous fluorocarbons exhausted from a vacuum processing chamber inwhich a semiconductor substrate is processed, the method comprising:processing the semiconductor substrate in the vacuum processing chamberthereby producing gaseous reaction products including the gaseousfluorocarbons; flowing an exhaust gas containing fluorocarbonsconsisting essentially of the gaseous fluorocarbons from the vacuumprocessing chamber through a reaction chamber downstream of the vacuumprocessing chamber; introducing water vapor as a reactant into theexhaust gas proximate to the vacuum processing chamber in an amounteffective to minimize recombination of dissociated fluorocarbons,hydrogen from the water vapor reacting with the dissociatedfluorocarbons to form HF, and oxygen from the water vapor reacting withat least one of C, S and N in the exhaust gas to form at least one ofthe gases COx, SOx, and NOx, or a mixture thereof in gaseous form;applying RF power to the gas in the reaction chamber to generate aplasma in the reaction chamber which dissociates the fluorocarbons inthe exhaust gas; and reacting gas exhausted from the reaction chamberwith at least one of Si and W downstream of the reaction chamber. 19.The method of claim 18, wherein generating a plasma in the reactionchamber by applying RF power to the gas comprises applying RF power toat least one transformer coupled plasma (TCP) coil to induce a planarmagnetic field which induces a flow of electrons within a planar regionparallel to the plane of the at least one TCP coil, wherein the flow ofelectrons creates a plasma by ionizing gas molecules.
 20. An abatementmethod for destroying fluorocarbons, consisting essentially of:processing a semiconductor substrate in a vacuum processing chamberthereby producing gaseous reaction products including gaseousfluorocarbons; flowing an exhaust gas containing the gaseous reactionproducts and fluorocarbons from the vacuum processing chamber through areactant mixing chamber proximate to the vacuum processing chamber andthen through a reaction chamber downstream from the reactant mixingchamber, wherein both the reactant mixing chamber and reaction chamberare in flow communication with the vacuum processing chamber;introducing water vapor into the exhaust gas in the reactant mixingchamber in an amount effective to reduce recombination of dissociatedfluorocarbons in the gaseous reaction products, hydrogen from the watervapor reacting with the dissociated fluorocarbons so as to form HF ingaseous form; generating a plasma in the plasma reactor by applying RFpower to the gas in the plasma reactor, the plasma dissociating thefluorocarbons in the exhaust gas; and optionally removing the HF fromthe exhaust gas downstream of the plasma reactor.
 21. The method ofclaim 20, wherein the water vapor is injected as the reactant into theexhaust gas in a foreline of the vacuum processing chamber proximate tothe vacuum processing chamber.
 22. The method of claim 20, whereingenerating a plasma in the reaction chamber by applying RF power to thegas comprises applying RF power to at least one transformer coupledplasma (TCP) coil to induce a planar magnetic field which induces a flowof electrons within a planar region parallel to the plane of the atleast one TCP coil, wherein the flow of electrons creates a plasma byionizing gas molecules.
 23. An abatement method for destroyingfluorocarbons, consisting essentially of: plasma etching a semiconductorsubstrate using gaseous fluorocarbons in a vacuum processing chamberthereby producing gaseous etch reaction products including dissociatedfluorocarbons; flowing an exhaust gas containing the remaining gaseousfluorocarbons and the dissociated fluorocarbons from the vacuumprocessing chamber through a reaction chamber in flow communication withthe vacuum processing chamber; introducing water vapor into the exhaustgas proximate to the vacuum processing chamber and upstream from thereaction chamber upstream from the reaction chamber in an amounteffective to reduce recombination of dissociated fluorocarbonsdissociated in the vacuum processing chamber, hydrogen from the watervapor reacting with the dissociated fluorocarbons so as to form HF ingaseous form; generating a plasma in the reaction chamber by applying RFpower to the exhaust gas in the reaction chamber, the plasmadissociating the gaseous fluorocarbons in the exhaust gas that were notpreviously dissociated in the vacuum processing chamber or wererecombined upstream from the reaction chamber, wherein the dissociatedgaseous fluorocarbons dissociated in the reaction chamber also reactwith hydrogen from the water vapor so as to form HF in gaseous form; andremoving the HF from the exhaust gas downstream of the reaction chamber.24. The method of claim 23, wherein the HF is removed by at least one ofa Si scrubber and a W scrubber in the form of at least one of beads,pellets, chunks, a liner, a baffle, a screen and a grid.
 25. The methodof claim 23, wherein generating a plasma in the reaction chamber byapplying RF power to the gas comprises applying RF power to at least onetransformer coupled plasma (TCP) coil to induce a planar magnetic fieldwhich induces a flow of electrons within a planar region parallel to theplane of the at least one TCP coil, wherein the flow of electronscreates a plasma by ionizing gas molecules.
 26. A fluorocarbon abatementmethod, comprising: processing a semiconductor substrate in a vacuumprocessing chamber using gaseous fluorocarbons thereby producing gaseousreaction products including dissociated fluorocarbons; flowing anexhaust gas of the remaining gaseous fluorocarbons and the dissociatedfluorocarbons from the vacuum processing chamber through a reactionchamber in flow communication with the vacuum processing chamber;introducing water vapor into the exhaust gas proximate to the vacuumprocessing chamber and upstream from the reaction chamber; generating aplasma in the reaction chamber by applying RF power to the exhaust gasand the water vapor in the reaction chamber, the plasma dissociating thegaseous fluorocarbons in the exhaust gas; and reacting gas exhaustedfrom the reaction chamber with one of Si and W.
 27. The method of claim26, wherein the water vapor is injected as the reactant in a foreline ofthe vacuum processing chamber proximate to the vacuum processingchamber.
 28. The method of claim 26 wherein the gas exhausted from thereaction chamber is reacted with at least one of a Si scrubber and a Wscrubber in the form of at least one of beads, pellets, chunks, a liner,a baffle, a screen and a grid.
 29. The method of claim 26, whereingenerating a plasma in the reaction chamber by applying RF power to thegas comprises applying RF power to at least one transformer coupledplasma (TCP) coil to induce a planar magnetic field which induces a flowof electrons within a planar region parallel to the plane of the atleast one TCP coil, wherein the flow of electrons creates a plasma byionizing gas molecules.